Methyl Jasmonate Treatment Eliminates Cell-Specific Expression of Vegetative Storage Protein Genes in Soybean Leaves

Soybean (Glycine max) plants accumulate a vacuolar glycoprotein in the parenchymal cells of leaves, petioles, stems, seed pods, and germinating cotyledons that acts in temporary nitrogen storage during vegetative growth. In situ immunolocalization of this vegetative storage protein (VSP) revealed that it accumulates in those parenchymal cells in close proximity to existing and developing vasculature, as well as in epidermal and cortical cells. The protein was more prevalent in younger, nitrogen-importing tissues before pod and seed development. Removal of actively growing seed pods greatly enhanced VSP accumulation, primarily in bundle sheath and paraveinal mesophyll cells. In situ hybridization of a VSP RNA probe to mRNA in leaf sections demonstrated that cell-specific mRNA accumulation corresponded with the pattern of protein localization. Treatment of leaf explants with 50 micromolar methyl jasmonate resulted in accumulation of VSP mRNA and protein in all cell types.